Sale of Balance Flats (SBF)
What is SBF (Sale of Balance Flats)?
A Sale of Balance Flats (SBF) is an HDB sales exercise for flats left over from earlier sales, including unselected flats from past BTO exercises, surplus SERS replacement flats and flats HDB has bought back. As with BTO, you need an HFE letter and a computerised ballot sets the booking order; flats still unselected are later offered through open booking.
Key facts
- What is sold
- Balance flats from earlier BTO exercises, surplus SERS replacement flats, repurchased flats and others
- Before applying
- You need a valid HDB Flat Eligibility (HFE) letter
- Selection
- A computerised ballot sets the queue order, as for BTO
- BTO and SBF together
- If one exercise has both, you can apply for one or the other, not both
- Flats not taken up
- Offered later through open booking, first come, first served
- Flat details
- Published on the HDB Flat Portal only during the SBF exercise
As of 6 Nov 2026. Source: HDB.
How SBF works
HDB has three ways of selling new flats:
| Mode | What it offers | How flats are allocated |
|---|---|---|
| Build-To-Order (BTO) | New flats in upcoming projects | Computerised ballot |
| Sale of Balance Flats (SBF) | Balance flats from earlier exercises, surplus SERS replacement flats, repurchased flats and others | Computerised ballot |
| Open booking | Flats not selected in past SBF exercises | First come, first served |
Some sales exercises include both BTO and SBF flats. Unlike BTO projects, whose details HDB shares one launch ahead, SBF flat details are published on the HDB Flat Portal only during the exercise.
Example
In a sales exercise that offers both BTO and SBF flats, a couple choose SBF and apply for a 4-room flat in one town. They can’t also apply for a BTO flat in the same exercise. If they are not successful, they can later look at unselected flats through open booking.
Common mistakes
- Applying for both BTO and SBF in one exercise. You can choose only one.
- Waiting for advance details. SBF flat details appear only when the exercise opens, so check the HDB Flat Portal then.
- Forgetting the HFE letter. You need a valid one before the application period opens.
Frequently asked questions
What is open booking of flats?
Open booking offers flats that were not selected in past SBF exercises. You apply online, receive a queue number on a first-come, first-served basis, and can book as early as the next working day, where possible.
Are SBF flats cheaper than BTO flats?
Not necessarily. SBF flats come from many different projects, so prices vary with location, flat type and age. HDB posts prices during the exercise.
Do the same rules apply after buying an SBF flat?
Yes. SBF flats are flats bought from HDB, so the usual conditions apply, including the minimum occupation period and any resale levy if you are a second-timer.
Related terms
Sources
Every figure on this page was checked against the official government sources above on 6 Nov 2026. See our editorial policy.
This is general information, not financial, legal or tax advice.